CN112733790B

CN112733790B - Fingerprint identification module, display panel, driving method of display panel and display device

Info

Publication number: CN112733790B
Application number: CN202110079487.7A
Authority: CN
Inventors: 姚绮君; 张波; 卢峰
Original assignee: Xiamen Tianma Microelectronics Co Ltd
Current assignee: Xiamen Tianma Microelectronics Co Ltd
Priority date: 2021-01-21
Filing date: 2021-01-21
Publication date: 2022-11-08
Anticipated expiration: 2041-01-21
Also published as: CN112733790A; US20220230009A1; US11749010B2

Abstract

The invention discloses a fingerprint identification module, a display panel, a driving method of the display panel and a display device, and belongs to the technical field of display, wherein the fingerprint identification module comprises a first electrode layer and a second electrode layer, wherein the first electrode layer comprises a plurality of first electrodes, the second electrode layer comprises a plurality of second electrodes which are arranged along a first direction, and one second electrode is overlapped with at least two first electrodes; and the flexible circuit board is bound and connected with the second electrode. The second electrode and the flexible circuit board are arranged in a second direction in a plane parallel to the first electrode layer. The display panel comprises the fingerprint identification module. The driving method of the display panel is used for driving the display panel to perform touch detection work and fingerprint identification work, and comprises the following steps: determining the touch position of the finger through the touch layer to complete touch detection work; the display device comprises the display panel. The invention can reduce the power loss of the fingerprint identification module, realize the ultrasonic fingerprint identification and improve the identification performance.

Description

Fingerprint identification module, display panel, driving method of display panel and display device

Technical Field

The invention relates to the technical field of display, in particular to a fingerprint identification module, a display panel, a driving method of the display panel and a display device.

Background

With the development of science and technology, a variety of display devices with fingerprint identification functions, such as mobile phones, tablet computers, intelligent wearable devices and the like, appear on the market. Since the fingerprint is unique to each person, the use of the fingerprint recognition function can increase the safety factor of the display device. Before a user operates the display device with the fingerprint identification function, the user can carry out authority verification only by touching the display device with a finger, and the authority verification process is simplified. Generally, fingerprint recognition technology can be classified into optical fingerprint recognition technology, silicon chip fingerprint recognition technology, and ultrasonic fingerprint recognition technology.

Currently, the ultrasonic fingerprint identification technology is the popular research direction of all manufacturers. The ultrasonic type under-screen fingerprint identification technology generally adopts high-voltage driving piezoelectric film layer to form ultrasonic waves. To obtain sufficient fingerprint signals, strong ultrasonic waves need to be formed by driving, and the driving voltage often reaches about 100V. And large-area ultrasonic fingers are arranged in the display screenThe line identification unit easily causes the capacitance in the whole driving loop to be large, and the driving process has higher power loss. For example for about 1cm ² The ultrasonic fingerprint identification unit has a parasitic capacitance of 1nF, a current peak value of 6A under the drive of 10MHz frequency and 100V peak voltage, and the power of the drive loop resistor of 1ohm can be up to 18w.

Therefore, it is an urgent technical problem to provide a fingerprint identification module, a display panel, a driving method thereof, and a display device, which can reduce power consumption, realize ultrasonic fingerprint identification, and improve identification performance.

Disclosure of Invention

In view of this, the present invention provides a fingerprint identification module, a display panel, a driving method thereof, and a display device, so as to solve the problem that the ultrasonic fingerprint identification module in the prior art has large power consumption and affects the identification performance.

The invention discloses a fingerprint identification module, which comprises: the first electrode layer comprises a plurality of first electrodes which are arranged in an array; the piezoelectric layer is positioned on one side of the first electrode layer; a second electrode layer located on a side of the piezoelectric layer away from the first electrode layer, the second electrode layer including a plurality of second electrodes arranged along the first direction, one second electrode overlapping at least two first electrodes; the flexible circuit board is bound and connected with the second electrode; the second electrode and the flexible circuit board are arranged along a second direction in a plane parallel to the first electrode layer; wherein the first direction intersects the second direction.

Based on the same inventive concept, the invention also discloses a display panel which comprises the fingerprint identification module.

Based on the same inventive concept, the invention also discloses a driving method of the display panel, which is used for driving the display panel to perform touch detection work and fingerprint identification work, and the driving method comprises the following steps: determining the touch position of the finger through the touch layer to complete touch detection work; determining a second electrode corresponding to the finger touch position; providing an excitation signal to only the second electrode corresponding to the finger touch position, connecting the first electrode to a common potential, and generating an ultrasonic wave by the piezoelectric layer between the second electrode corresponding to the finger touch position and the first electrode; and carrying out ultrasonic fingerprint identification on the driving circuit corresponding to the second electrode corresponding to the finger touch position to finish fingerprint identification work.

Based on the same inventive concept, the invention also discloses a display device, which comprises the display panel.

Compared with the prior art, the fingerprint identification module, the display panel, the driving method of the display panel and the display device provided by the invention at least realize the following beneficial effects:

the fingerprint identification module in the invention is provided with a second electrode layer comprising a plurality of second electrodes, the second electrodes can be used as driving electrodes, and the flexible circuit board used for providing driving voltage signals for the fingerprint identification module and reading fingerprint detection signals is directly bound and connected with the second electrodes. In the prior art, the second electrode is generally connected with the flexible circuit board through a thin lead wire to realize the transmission of electric signals, the difference between the width of the lead wire used as a routing wire and the width of the second electrode used as a driving electrode is larger, and the width of the common routing wire is much smaller, even only a few hundredths or even a few thousandths of the width of the second electrode; the size of the line width affects the size of the cross-sectional area of the resistor, and thus the size of the resistor, and the smaller the line width, the smaller the cross-sectional area, the larger the resistance, so that the resistance of the lead used as a trace is much larger than the resistance of the second electrode used as a driving electrode under otherwise substantially the same conditions. Therefore, the flexible circuit board used for providing a driving voltage signal for the fingerprint identification module and reading a fingerprint detection signal is directly bound and connected with the second electrode, and a lead is not used in the module structure, so that the serious power loss caused by the loss of the driving signal transmitted between the flexible circuit board and the second electrode due to the arrangement of the lead with larger impedance can be effectively avoided, the power loss of the fingerprint identification module can be further reduced, the ultrasonic fingerprint identification is realized, the identification performance is improved, meanwhile, when a touch event occurs, the flexible circuit board only provides an alternating current signal for the second electrode related to the touch event, and the rest of the second electrodes do not provide signals, so that the power supply area can be reduced, the capacitive load during driving is reduced, and the purpose of reducing the power consumption is further achieved.

Of course, it is not necessary for any product in which the present invention is practiced to specifically achieve all of the above-described technical effects simultaneously.

Other features of the present invention and advantages thereof will become apparent from the following detailed description of exemplary embodiments of the invention, which proceeds with reference to the accompanying drawings.

Drawings

The accompanying drawings, which are incorporated in and constitute a part of this specification, illustrate embodiments of the invention and together with the description, serve to explain the principles of the invention.

Fig. 1 is a schematic plan view of a fingerprint identification module according to an embodiment of the present invention;

FIG. 2 is a schematic cross-sectional view taken along line B-B' of FIG. 1;

FIG. 3 is a schematic diagram of a planar structure of another fingerprint identification module according to an embodiment of the present invention;

FIG. 4 is a schematic diagram of a planar structure of another fingerprint identification module according to an embodiment of the present invention;

FIG. 5 is a schematic diagram of a planar structure of another fingerprint identification module according to an embodiment of the present invention;

FIG. 6 is a schematic diagram of a planar structure of another fingerprint identification module according to an embodiment of the present invention;

FIG. 7 is a schematic diagram of a planar structure of another fingerprint identification module according to an embodiment of the present invention;

FIG. 8 is a schematic diagram of a planar structure of another fingerprint identification module according to an embodiment of the present invention;

FIG. 9 is a schematic cross-sectional view taken along line C-C' of FIG. 8;

FIG. 10 is a schematic cross-sectional view taken along line D-D' of FIG. 7;

FIG. 11 is a schematic view of an alternative cross-sectional configuration in the direction of C-C' of FIG. 8;

FIG. 12 is a schematic diagram of a planar structure of another fingerprint identification module according to an embodiment of the present invention;

FIG. 13 is a schematic cross-sectional view taken along line E-E' of FIG. 12;

fig. 14 is a schematic diagram of an equivalent circuit connection structure of a plurality of driving circuits of the driving circuit layer according to an embodiment of the present invention;

FIG. 15 is a schematic diagram of a connection structure of one of the driving circuits in FIG. 14;

fig. 16 is an operation timing chart of the driving circuit;

fig. 17 is a schematic plan view of a display panel according to an embodiment of the present invention;

FIG. 18 is a schematic sectional view along line F-F' of FIG. 17;

FIG. 19 is a schematic view of another cross-sectional configuration in the direction F-F' of FIG. 17;

fig. 20 is a flowchart illustrating a driving method of a display panel according to an embodiment of the invention;

fig. 21 is a schematic flow chart of a driving method of a display panel according to an embodiment of the invention;

fig. 22 is a schematic plan view of a display device according to an embodiment of the present invention.

Detailed Description

Various exemplary embodiments of the present invention will now be described in detail with reference to the accompanying drawings. It should be noted that: the relative arrangement of the components and steps, the numerical expressions and numerical values set forth in these embodiments do not limit the scope of the present invention unless it is specifically stated otherwise.

The following description of at least one exemplary embodiment is merely illustrative in nature and is in no way intended to limit the invention, its application, or uses.

Techniques, methods, and apparatus known to those of ordinary skill in the relevant art may not be discussed in detail but are intended to be part of the specification where appropriate.

In all examples shown and discussed herein, any particular value should be construed as merely illustrative, and not limiting. Thus, other examples of the exemplary embodiments may have different values.

It should be noted that: like reference numbers and letters refer to like items in the following figures, and thus, once an item is defined in one figure, it need not be discussed further in subsequent figures.

Referring to fig. 1 and fig. 2, fig. 1 is a schematic plan structure diagram of a fingerprint identification module according to an embodiment of the present invention, fig. 2 is a schematic cross-sectional structure diagram along the direction B-B' in fig. 1 (it can be understood that, in order to clearly illustrate the position relationship between the first electrode layer and the second electrode layer, transparency filling is performed in fig. 1), the fingerprint identification module 000 according to the embodiment includes:

the first electrode layer 10 comprises a plurality of first electrodes 101, and the plurality of first electrodes 101 are arranged in an array;

a piezoelectric layer 20, the piezoelectric layer 20 being located at one side of the first electrode layer 10;

a second electrode layer 30 located on a side of the piezoelectric layer 20 away from the first electrode layer 10, the second electrode layer 30 including a plurality of second electrodes 301, the plurality of second electrodes 301 being arranged along the first direction X; alternatively, the adjacent second electrodes 301 may be insulated from each other; one second electrode 301 overlaps with at least two first electrodes 101;

the flexible circuit board 40 (not filled in the figure 1) is fixedly connected with the second electrode 301; the second electrodes 301 and the flexible circuit board 40 are arranged in the second direction Y in a plane parallel to the first electrode layer 10; wherein the first direction X intersects the second direction Y. Optionally, the first direction X and the second direction Y are perpendicular to each other in a plane parallel to the first electrode layer 10. Optionally, as shown in fig. 2, the structure of the fingerprint identification module 000 may be fabricated on the substrate 00, and the substrate 00 is used for bearing the film structure of the fingerprint identification module 000.

Specifically, the fingerprint identification module 000 of this embodiment is a fingerprint identification module using an ultrasonic technology, the fingerprint identification module 000 mainly includes three laminated structures of a first electrode layer 10, a piezoelectric layer 20, and a second electrode layer 30, the first electrode layer 10 may include a plurality of first electrodes 101, the plurality of first electrodes 101 are arranged in an array, and optionally, the adjacent first electrodes 101 may be in an insulated structure; the second electrode layer 30 located on the side of the piezoelectric layer 20 away from the first electrode layer 10 may include a plurality of second electrodes 301 insulated from each other, the plurality of second electrodes 301 are arranged along the first direction X, and the second electrodes 301 overlap at least two first electrodes 101; alternatively, the piezoelectric layer 20 may be entirely laid on the surface of the first electrode layer 20, and then the second electrode 301 may be used as a driving electrode (transmitting end), and the first electrode 101 may be used as a receiving electrode (receiving end). When the fingerprint identification module 000 of this embodiment performs fingerprint identification, an alternating current signal can be provided to the second electrode 301 through the flexible circuit board 40, and the driving voltage loaded between the first electrode 101 and the second electrode 301 changes continuously, so that the piezoelectric layer 20 generates vibration and emits ultrasonic waves; when touch recognition is performed on a touch main body such as a finger, the fingerprint comprises valleys and ridges, so that the ultrasonic vibration intensity reflected back to the piezoelectric layer 20 by the fingerprint has differences, the change of electric signals generated when the valleys and the ridges are reflected back to the piezoelectric layer 20 is different, the positions of the valleys and the ridges in the fingerprint are judged according to the voltage signals with different changes, the judgment result is fed back to the first electrode 101, and finally the fingerprint image can be read by the flexible circuit board 40 and subjected to data conversion to form the fingerprint image, so that the fingerprint recognition work is completed.

In the fingerprint identification module 000 in this embodiment, the second electrode layer 30 includes a plurality of second electrodes 301 insulated from each other (the second electrode layer includes three second electrodes for example in fig. 1), and the flexible circuit board 40 for providing a driving voltage signal for the fingerprint identification module 000 and reading a fingerprint detection signal is directly bonded to the second electrodes 301, that is, as shown in fig. 1 and fig. 2, the second electrodes 301 are arranged to extend all the way to the area where the flexible circuit board 40 is located and partially overlap with the flexible circuit board 40, so that the flexible circuit board 40 is directly bonded to the second electrodes 301. Because the second electrode 301 is generally connected to the flexible circuit board 40 through a thin lead wire in the prior art, transmission of an electrical signal is achieved, and the width of the lead wire used as a trace has a larger difference from the width of the second electrode 301 used as a driving electrode, and the width of the common trace is much smaller, even only a few hundredths or even a few thousandths of the width of the second electrode 301; according to the calculation formula of the resistance: r = ρ L/S, R is resistance, ρ is resistivity, L is resistance length, S is resistance cross-sectional area, the size of the line width affects the size of the resistance cross-sectional area, and thus the size of the resistance, and the smaller the line width, the smaller the cross-sectional area, the larger the resistance, so that the resistance of the lead wire used as the trace is much larger than the resistance of the second electrode 301 used as the drive electrode under otherwise substantially the same conditions. Therefore this embodiment sets up and is used for providing the flexible circuit board 40 that drive voltage signal and read fingerprint detection signal for fingerprint identification module 000 and second electrode 301 direct binding is connected, do not use the lead wire in the module structure, thereby can effectively avoid great because of setting up lead wire impedance, lead to the drive signal loss of transmission between flexible circuit board 40 and the second electrode 301, cause more serious power loss, and then can reduce the power loss of fingerprint identification module 000, realize ultrasonic fingerprint identification, improve the recognition performance.

In the fingerprint identification module 000 provided in this embodiment, the plurality of first electrodes 101 of the first electrode layer 10 are arranged in an array of a plurality of rows and a plurality of columns, and the plurality of second electrodes 301 of the second electrode layer 30 are only in a structure of a plurality of rows and a plurality of columns, that is, in the second direction Y, there is only one row of second electrodes 301, and in the first direction X, there are a plurality of second electrodes 301 arranged in sequence. Optionally, one second electrode 301 of the present embodiment overlaps at least two first electrodes 101. In this embodiment, the number of the second electrodes 301 of the second electrode layer 30 is set to be plural, and the plural second electrodes 301 are arranged along the first direction X, in the second direction, each second electrode 301 is directly bound and electrically connected with the flexible circuit board 40, so that when fingerprint identification is performed, each second electrode 301 is respectively driven, that is, when a touch event occurs, the flexible circuit board 40 only provides an alternating current signal for the second electrode 301 related to the touch event, and the remaining second electrodes 301 do not provide a signal, only the driving voltage loaded between the first electrode 101 and the second electrode 301 at the position where the touch event occurs changes continuously, so that the piezoelectric layer 20 generates vibration and emits ultrasonic waves, because the fingerprint includes valleys and ridges, the ultrasonic vibration intensity reflected back to the piezoelectric layer 20 by the fingerprint is different, so that the changes of the electric signals generated by the valleys and the ridges reflected back to the piezoelectric layer 20 are different, the positions of the valleys and the ridges in the fingerprint are determined according to the voltage signals with different changes, and the determination result is fed back to the first electrode 101 at the position where the touch event occurs, and finally, data conversion can be read by the flexible circuit board 40 to form an image, and perform fingerprint identification work.

Therefore, the number of the second electrodes 301 of the second electrode layer 30 is set to be plural in this embodiment, and the plural second electrodes 301 are along the first direction X, in the second direction, each second electrode 301 is directly bound with the flexible circuit board 40 to be electrically connected, no lead is used in the module structure, thereby effectively avoiding the loss of the driving signal transmitted between the flexible circuit board 40 and the second electrode 301 due to the setting of a lead with large impedance, causing a serious power loss, further reducing the power loss of the fingerprint identification module 000, realizing the ultrasonic fingerprint identification, improving the identification performance, and at the same time of the occurrence of a touch event, the flexible circuit board 40 only provides an alternating current signal for the second electrode 301 related to the touch event, and the rest of the second electrodes 301 do not provide a signal, thereby reducing the power supply area, reducing the capacitive load during driving, and being beneficial to further achieving the purpose of reducing the power consumption.

It should be understood that fig. 1 and fig. 2 of the present embodiment only show the schematic structural diagram of the fingerprint identification module 000 by way of example, but not limited to this structure, and may also include other structures, and the present embodiment is not limited in particular. Optionally, the manufacturing materials of the first electrode layer 10 and the second electrode layer 30 of this embodiment may be both metal materials, which are used to manufacture the first electrode 101 and the second electrode 301, and the metal materials have better conductivity, and at the same time, the binding connection effect between the second electrode 301 and the flexible circuit board 40 may be better. The piezoelectric layer 20 of this embodiment can be made of piezoelectric material with higher piezoelectric voltage constant such as PVDF (polyvinylidene fluoride), so that the fingerprint identification module 000 of this embodiment has higher receiving sensitivity to ultrasonic waves, which is beneficial to improving fingerprint identification performance.

In some optional embodiments, please refer to fig. 1, fig. 2 and fig. 3 in combination, fig. 3 is a schematic plane structure diagram of another fingerprint identification module according to an embodiment of the present invention (it can be understood that transparency filling is performed in fig. 3 to clearly illustrate a position relationship between the first electrode layer and the second electrode layer), in this embodiment, the flexible circuit board 40 includes a plurality of pins 401, and one second electrode 301 is connected to one pin 401 in a binding manner.

This embodiment explains that when the second electrode 301 is arranged to extend to the area where the flexible circuit board 40 is located and partially overlap with the flexible circuit board 40, so as to achieve direct bonding connection between the flexible circuit board 40 and the second electrode 301, the flexible circuit board 40 may include a plurality of pins 401, and one second electrode 301 is bonded to one pin 401 (as shown in fig. 3), so as to achieve the effect of providing a driving signal for each second electrode 301.

Optionally, the ratio of the width W1 of one pin 401 to the width W2 of one second electrode 301 along the first direction X may be in a range of 0.9-1.1, that is, the width W1 of one pin 401 is substantially the same as the width W2 of one second electrode 301 along the first direction X, so as to facilitate that one second electrode 301 directly extends along the second direction Y to be bound and connected with one pin 401 of the flexible circuit board 40.

Further alternatively, in consideration of process variations, a ratio of the width W1 of one lead 401 to the width W2 of one second electrode 301 along the first direction X may range from 0.9 to 1, i.e., the width W1 of one lead 401 may be slightly smaller than the width W2 of one second electrode 301.

In some optional embodiments, please refer to fig. 1, fig. 2 and fig. 4 in combination, and fig. 4 is a schematic plane structure diagram of another fingerprint identification module according to an embodiment of the present invention (it can be understood that transparency filling is performed in fig. 4 to clearly illustrate a position relationship between the first electrode layer and the second electrode layer), in this embodiment, the flexible circuit board 40 includes a plurality of pins 401, and one second electrode 301 is connected to the plurality of pins 401 disposed at intervals in a binding manner.

The embodiment explains that the second electrode 301 extends to the area where the flexible circuit board 40 is located, and is partially overlapped with the flexible circuit board 40, so that when the flexible circuit board 40 is directly bonded and connected with the second electrode 301, the flexible circuit board 40 may include a plurality of pins 401, and one second electrode 301 is bonded and connected with a plurality of pins 401 arranged at intervals (as shown in fig. 4).

In some optional embodiments, please refer to fig. 5, where fig. 5 is a schematic plane structure diagram of another fingerprint identification module provided in the embodiments of the present invention (it can be understood that, in order to clearly illustrate the position relationship between the first electrode layer and the second electrode layer, transparency filling is performed in fig. 5), in the fingerprint identification module 000 provided in this embodiment, the number of the second electrodes 301 is plural, and the plural second electrodes 301 are arranged along the first direction X;

each second electrode 301 may include a first sub-portion 3011 and a second sub-portion 3012, which are integrally formed and adjacent to each other in the second direction Y, where the first sub-portion 3011 is a portion bound to the flexible circuit board 40, and the second sub-portion 3012 is the rest of the second electrode 301; the width W7 of the second sub-portion 3012 may be greater than the width W8 of the first sub-portion 3011 along the first direction X.

This embodiment explains that in the fingerprint recognition module 000, the number of the second electrodes 301 is plural, the plural second electrodes 301 are arranged along the first direction X, and when the flexible circuit board 40 includes the plural pins 401, and one second electrode 301 is bound and connected to one pin 401, a portion of the second electrode 301 bound and connected to the flexible circuit board 40 may be set to be narrower, and the rest may be wider, that is, each second electrode 301 may include a first sub-portion 3011 and a second sub-portion 3012 which are integrally structured and adjacent to each other in the second direction Y, where the first sub-portion 3011 is a portion bound and connected to the flexible circuit board 40, and the second sub-portion 3012 is the rest of the second electrode 301; along the first direction X, the width W7 of the second sub-portion 3012 may be greater than the width W8 of the first sub-portion 3011, for example, the width W8 of the first sub-portion 3011 is 1/2, or 1/3, etc. of the width W7 of the second sub-portion 3012, so that while the second electrode 301 is directly bonded and connected to one pin 401 on the flexible circuit board 40, the area of the pin 401 on the flexible circuit board 40 may also be reduced, which is further beneficial to reducing the area of the flexible circuit board 40, so as to save the occupied space of the flexible circuit board 40, and is beneficial to implementing miniaturization development of the whole fingerprint identification module 000.

In some alternative embodiments, please refer to fig. 6, where fig. 6 is a schematic plan view of another fingerprint identification module provided in the embodiments of the present invention (it can be understood that, in order to clearly illustrate a position relationship between the first electrode layer and the second electrode layer, transparency filling is performed in fig. 6), in the embodiments, the second electrode 301 has a rectangular shape, and a length of the second electrode 301 along the first direction X is a, and a length of the second electrode 301 along the second direction Y is B, where B > a.

The present embodiment explains that the shape of the row and column of the second electrodes 301 disposed on the second electrode layer 30 may be rectangular, that is, along the first direction X, the length of the second electrode 301 is a, along the second direction Y, the length of the second electrode 301 is B, where B > a, and the second electrode 301 is a rectangle whose length in the second direction Y is greater than the length in the first direction X, since the size of the fingerprint contact in the fingerprint identification technology is generally a square structure, while in the present embodiment, in order to reduce the power loss, each second electrode 301 is directly extended to the overlapping position with the flexible circuit board 40 and directly overlaps with the flexible circuit board 40, so that the shape of the second electrode 301 is designed to be rectangular, and the portion of each second electrode 301 overlapping and bound with the flexible circuit board 40 can be removed, and the rest portions can form a square structure as much as possible, so as to meet the shape and size requirements for fingerprint identification.

Alternatively, as shown in FIG. 6, the area size typically required to discriminate fingerprints is typically 25mm ² Left and right, therefore, when a touch event occurs, if a touch subject such as a finger is located on only one second electrode 301, the second electrode 301 is along a first directionThe length A of the X can be designed to be 4-5mm, the length B of the second electrode 301 along the second direction Y can be designed to be 6-8mm, and the area occupied by the flexible circuit board 40 can be reduced in the second direction Y, so that the area of a fingerprint identification area can be increased. In this embodiment, when a touch event occurs, the flexible circuit board 40 only provides an alternating current signal for the second electrode 301 related to the touch event, and the other second electrodes 301 do not provide a signal, so that the power supply area can be reduced, the capacitive load during driving can be reduced, the purpose of reducing power consumption can be further achieved, and simultaneously, it can be satisfied that each second electrode 301 is removed from the overlapping and binding portion with the flexible circuit board 40, and the remaining portion (as shown in the region C1 in fig. 6) can form a square as much as possible, and at the same time, it can also be satisfied that the square area of the remaining portion is 25mm as much as possible ² Left and right, i.e. at least one size of area required for discriminating a fingerprint.

In some optional embodiments, please refer to fig. 7, fig. 7 is a schematic plan view of another fingerprint identification module according to an embodiment of the present invention (it can be understood that, in order to clearly illustrate a position relationship between the first electrode layer and the second electrode layer, transparency filling is performed in fig. 7), in this embodiment, the second electrode 301 has a rectangular shape, and along the first direction X, the length of the second electrode 301 is a, and along the second direction Y, the length of the second electrode 301 is B, where B > a, at this time, a length of a fingerprint identification area (i.e., an area where a touch subject touches the fingerprint identification module to enable fingerprint detection) of the fingerprint identification module 000 of this embodiment along the second direction Y is K, where B > K; the length A of the second electrode 301 along the first direction X is larger than or equal to 2mm and smaller than or equal to 5mm, and the length B of the second electrode 301 along the second direction Y is larger than or equal to 5mm. Alternatively, the length B of the second electrode 301 in the second direction Y may be designed to be 6-8mm.

This embodiment explains that the shape of the row and column of the second electrodes 301 disposed on the second electrode layer 30 may be rectangular, and along the first direction X, the length of the second electrode 301 is a, which satisfies 2mm ≦ a ≦ 5mm, and along the second direction Y, the length B of the second electrode 301 satisfies B > 5mm, optionally, the length B of the second electrode 301 along the second direction Y may be designed to be 6-8mm, and may be in the second direction YIn the two directions Y, the area occupied by the flexible circuit board 40 is reduced, which is beneficial to increasing the area of the fingerprint identification area. In this embodiment, when a touch event occurs, if a touch subject, such as a finger, is located on the two second electrodes 301, when the touch event occurs, the flexible circuit board 40 only provides an alternating current signal for the two second electrodes 301 involved in the touch event, and the remaining second electrodes 301 do not provide a signal, so that a power supply area can be reduced, a capacitive load during driving can be reduced, and a purpose of reducing power consumption is further achieved, and meanwhile, it can be satisfied that the two second electrodes 301 involved in the touch event are removed from a portion overlapped and bound with the flexible circuit board 40, and a remaining portion (e.g., a region C2 in fig. 7) can also form a square as much as possible while a sum of square areas of the remaining portions of the two second electrodes 301 is 25mm as much as possible ² Left and right, i.e. at least the size of an area required for discriminating a fingerprint.

In some alternative embodiments, please refer to fig. 8 and 9 in combination, fig. 8 is a schematic plane structure diagram of another fingerprint identification module provided in the embodiments of the present invention, fig. 9 is a schematic cross-sectional structure diagram along the direction C-C' in fig. 8 (it can be understood that, in order to clearly illustrate the position relationship between the first electrode layer and the second electrode layer, transparency filling is performed in fig. 8), in the fingerprint identification module 000 provided in this embodiment, a retaining wall 50 is disposed between two adjacent second electrodes 301.

The present embodiment explains a structure in which the plurality of first electrodes 101 of the first electrode layer 10 are arranged in an array of rows and columns, and the plurality of second electrodes 301 of the second electrode layer 30 are arranged in only one row and columns, that is, in the second direction Y, there is only one row of second electrodes 301, and in the first direction X, there are a plurality of second electrodes 301 arranged in sequence. Optionally, one second electrode 301 of the present embodiment overlaps at least two first electrodes 101. In the embodiment, the number of the second electrodes 301 of the second electrode layer 30 is set to be multiple, and the multiple second electrodes 301 are arranged along the first direction X, in the second direction, each second electrode 301 is directly bound and electrically connected with the flexible circuit board 40, when a touch event occurs, the flexible circuit board 40 only provides an alternating current signal for the second electrode 301 involved in the touch event, and the rest of the second electrodes 301 do not provide a signal, so that the power supply area can be reduced, the capacitive load during driving is reduced, and the purpose of reducing power consumption is further achieved. In addition, while the plurality of second electrodes 301 are arranged along the first direction X, the retaining wall 50 is disposed between two adjacent second electrodes 301, so as to insulate the two adjacent second electrodes 301, and fill up the gap between the two adjacent second electrodes 301, which is beneficial to the flatness of the entire fingerprint identification module 000.

Alternatively, as shown in fig. 8, the retaining wall 50 extends along the second direction Y, and an orthographic projection of the retaining wall 50 to the plane of the flexible circuit board 40 at least partially overlaps the flexible circuit board 40.

The embodiment explains that the retaining wall 50 for insulating the two second electrodes 301 may extend to the position overlapping with the flexible circuit board 40 along the second direction Y, so that the gap between two adjacent pins 401 on the flexible circuit board 40 may be filled, which helps to improve the bonding yield of the second electrodes 301 and the flexible circuit board 40.

In some optional embodiments, when the second electrode layer 30 is manufactured, a vacuum process such as a sputtering process may be used for preparation, and since the second electrode layer 30 manufactured by the sputtering process is thinner, the retaining wall 50 may not be disposed between two adjacent second electrodes 301, which is beneficial to reducing the process steps and improving the process efficiency.

In some optional embodiments, please refer to fig. 7 and fig. 10 in combination, fig. 10 is a schematic cross-sectional structure diagram along direction D-D' in fig. 7, the fingerprint identification module 000 provided in this embodiment further includes a driving circuit layer 60, the driving circuit layer 60 is electrically connected to the first electrode layer 10 (an electrical connection relationship is not illustrated in fig. 10, it can be understood that an insulating layer may be included between the driving circuit layer 60 and the first electrode layer 10, and the insulating layer is not filled in fig. 10); optionally, the driving circuit layer 60 may be disposed between the substrate 00 and the first electrode layer 10, so as to be electrically connected to the first electrode layer 10;

the driving circuit layer 60 includes a plurality of driving circuits 601, the plurality of driving circuits 601 are arranged in an array, and fig. 10 shows the driving circuits as a block diagram, in a specific implementation, the structure of the driving circuit 601 manufactured in the driving circuit layer 60 may be a circuit connection structure including transistors, capacitors, signal lines, and the like, and this embodiment is not particularly limited, and only needs to satisfy that the driving circuit 601 can realize a fingerprint identification function of an ultrasonic technology; optionally, the driving circuits 601 in the driving circuit layer 60 may be electrically connected to the first electrodes 101 in a one-to-one correspondence;

in a plane parallel to the first electrode layer 10, the interval between two adjacent second electrodes 301 is located between two adjacent columns of driving circuits 601.

The embodiment explains that the driving signal between the first electrode 101 and the second electrode 301 can be driven by each driving circuit 601 of the driving circuit layer 60, optionally, the driving circuit layer 60 can be disposed between the substrate 00 and the first electrode layer 10 to realize electrical connection with the first electrode layer 10, the embodiment is disposed in a plane parallel to the first electrode layer 10, and the interval between two adjacent second electrodes 301 is located between two adjacent columns of driving circuits 601, so that the interval between two adjacent second electrodes 301 does not involve the driving circuit 601, which is beneficial to generating a better driving induction relationship between the second electrode 301 and each corresponding driving circuit 601. When a touch event occurs, the flexible circuit board 40 provides an alternating current signal and each driving signal only for the second electrode 301 related to the touch event through the driving circuit 601, and the other second electrodes 301 do not provide signals, only the driving voltage loaded between the first electrode 101 and the second electrode 301 at the position where the touch event occurs changes continuously, so that the piezoelectric layer 20 generates vibration and emits ultrasonic waves, because the fingerprint comprises valleys and ridges, the vibration intensity of the ultrasonic waves reflected back to the piezoelectric layer 20 by the fingerprint is different, so that the changes of the electric signals generated by the valleys and the ridges reflected back to the piezoelectric layer 20 are different, the positions of the valleys and the ridges in the fingerprint are judged according to the voltage signals with different changes, and the judgment result is fed back to the first electrode 101 at the position where the touch event occurs, and finally the fingerprint image is formed by reading and data conversion through the flexible circuit board 40 through the driving circuit 601, so that the fingerprint identification work is completed.

In some optional embodiments, please refer to fig. 8 and fig. 11 in combination, fig. 11 is another schematic cross-sectional structure diagram along the direction C-C' in fig. 8, in the fingerprint identification module 000 provided in this embodiment, a driving circuit layer 60 is further included, the driving circuit layer 60 is electrically connected to the first electrode layer 10 (the electrical connection relationship is not illustrated in fig. 11, it is understood that an insulating layer may be included between the driving circuit layer 60 and the first electrode layer 10, and is not filled in fig. 11); optionally, the driving circuit layer 60 may be disposed between the substrate 00 and the first electrode layer 10, so as to be electrically connected to the first electrode layer 10; a retaining wall 50 for insulation is arranged between two adjacent second electrodes 301;

in a plane parallel to the first electrode layer 10, the retaining wall 50 between two adjacent second electrodes 301 is located between two adjacent columns of driving circuits 601.

The embodiment explains that the driving signal between the first electrode 101 and the second electrode 301 can be driven by each driving circuit 601 of the driving circuit layer 60, optionally, the driving circuit layer 60 can be disposed between the substrate 00 and the first electrode layer 10 to realize electrical connection with the first electrode layer 10, the embodiment is disposed in a plane parallel to the first electrode layer 10, and the barrier wall 50 between two adjacent second electrodes 301 is located between two adjacent columns of driving circuits 601, so that overlap between the driving circuit 601 and the barrier wall 50 can be avoided as much as possible, which is beneficial to generating a better driving induction relationship between the second electrode 301 and each corresponding driving circuit 601. When a touch event occurs, the flexible circuit board 40 provides an alternating current signal and each driving signal only for the second electrode 301 related to the touch event through the driving circuit 601, and the other second electrodes 301 do not provide signals, only the driving voltage loaded between the first electrode 101 and the second electrode 301 at the position where the touch event occurs changes continuously, so that the piezoelectric layer 20 generates vibration and emits ultrasonic waves, because the fingerprint comprises valleys and ridges, the vibration intensity of the ultrasonic waves reflected back to the piezoelectric layer 20 by the fingerprint is different, so that the changes of the electric signals generated by the valleys and the ridges reflected back to the piezoelectric layer 20 are different, the positions of the valleys and the ridges in the fingerprint are judged according to the voltage signals with different changes, and the judgment result is fed back to the first electrode 101 at the position where the touch event occurs, and finally the fingerprint image is formed by reading and data conversion through the flexible circuit board 40 through the driving circuit 601, so that the fingerprint identification work is completed.

It should be noted that fig. 10 and fig. 11 of this embodiment only exemplarily show the structure of the driving circuit layer 60, and in implementation, the driving circuit layer 60 may include multiple metal conductive film layers for manufacturing the transistors, capacitors, and other structures of the driving circuits 601, and the structure of the multiple metal conductive film layers of the driving circuit layer 60 is not particularly limited in this embodiment and may be set according to the actual circuit connection structure of the driving circuits 601.

In some optional embodiments, please refer to fig. 12 and fig. 13 in combination, where fig. 12 is a schematic plane structure diagram of another fingerprint identification module provided in the embodiments of the present invention, fig. 13 is a schematic cross-sectional structure diagram along the direction E-E' in fig. 12 (it can be understood that, in order to clearly illustrate the position relationship between the first electrode layer and the second electrode layer, transparency filling is performed in fig. 12), in the fingerprint identification module 000 provided in the embodiment, the driving circuit layer 60 at least includes a common signal line DB, and the common signal line DB is arranged to extend along the second direction Y; the common signal line DB includes at least a first common signal line DB1;

the orthographic projection of the first common signal line DB1 to the plane of the first electrode layer 10 at least partially overlaps with the orthographic projection of the retaining wall 50 to the plane of the first electrode layer 10.

The present embodiment explains that the driving circuit layer 60 is provided with a plurality of common signal lines DB, an optional common signal line DB is electrically connected to each driving circuit 601 (not shown), the common signal line DB is used for providing a common voltage signal for each driving circuit 601, the present embodiment provides that the common signal line DB is arranged to extend along the second direction Y, and an orthographic projection of the first common signal line DB1 in the common signal line DB to the plane of the first electrode layer 10 at least partially overlaps with an orthographic projection of the bank 50 to the plane of the first electrode layer 10, that is, the driving circuit layer 60 at the bank 50 position is provided with the first common signal line DB1, and the bank 50 overlaps with the first common signal line DB1, since the bank 50 functions to insulate the two adjacent second electrodes 301, the bank 50 generally has a wider width in the first direction X, and therefore, the first common signal line DB1 is arranged at the position overlapping with the bank 50, which is beneficial to further reducing power consumption loss by increasing the line width of the first common signal line DB1, and further making it possible to read fingerprint information and convert the fingerprint image, and thus beneficial to improve dynamic range of the driving circuit 601 to uniformize sampling range.

Optionally, the orthographic projection of the first common signal line DB1 onto the plane of the first electrode layer 10 and the orthographic projection of the retaining wall 50 onto the plane of the first electrode layer 10 may only partially overlap, and the orthographic projection of the first common signal line DB1 onto the plane of the first electrode layer 10 may also be completely located within the orthographic projection range of the retaining wall 50 onto the plane of the first electrode layer 10, that is, the orthographic projection of the retaining wall 50 onto the plane of the first electrode layer 10 may cover the orthographic projection of the first common signal line DB1 onto the plane of the first electrode layer 10 (as shown in fig. 13), so as to further increase the line width of the first common signal line DB1, and further reduce the power consumption loss of the driving circuit 601.

In some alternative embodiments, with continuing reference to fig. 12 and 13, in this embodiment, the common signal line DB for providing the common voltage signal for each driving circuit 601 further includes a second common signal line DB2, a forward projection of the second common signal line DB2 onto the plane of the first electrode layer 10 is not overlapped with a forward projection of the dam 50 onto the plane of the first electrode layer 10, and a line width W4 of the second common signal line DB2 is smaller than a line width W3 of the first common signal line DB 1.

The present embodiment explains that the driving circuits 601 in the driving circuit layer 60 can be electrically connected to the first electrodes 101 in a one-to-one correspondence, in addition to the first common signal line DB1 overlapped with the retaining wall 50, a second common signal line DB2 extending along the second direction Y can be provided at the spacing position of the first electrodes 101 in two adjacent columns in the driving circuit layer 60 to provide a common voltage signal for each driving circuit 601, since the orthographic projection of the second common signal line DB2 to the plane of the first electrode layer 10 is not overlapped with the orthographic projection of the retaining wall 50 to the plane of the first electrode layer 10, the present embodiment provides the line width W4 of the second common signal line DB2 to be smaller than the line width W3 of the first common signal line DB1, which is beneficial to saving the layout space of the driving circuit layer 60, and avoids providing too many common signal lines with wider line widths to cause the space reduction of the driving circuit layer 60, thereby being beneficial to the reasonable layout of each component in the driving circuit 601 of the driving circuit layer 60.

In some alternative embodiments, with continuing reference to fig. 12 and 13, in this embodiment, the common signal line DB for providing the common voltage signal for each driving circuit 601 includes a first common signal line DB1 and a second common signal line DB2, wherein the first common signal line DB1 and the second common signal line DB2 are both disposed along the second direction Y, an orthographic projection of the first common signal line DB1 onto the plane of the first electrode layer 10 at least partially overlaps with an orthographic projection of the dam 50 onto the plane of the first electrode layer 10, an orthographic projection of the second common signal line DB2 onto the plane of the first electrode layer 10 does not overlap with an orthographic projection of the dam 50 onto the plane of the first electrode layer 10, and a line width W4 of the second common signal line DB2 is smaller than a line width W3 of the first common signal line DB1;

the driving circuit layer 60 further includes a plurality of sub-connection lines DB3, the plurality of sub-connection lines DB3 being connected to each other by a common signal line DB, the sub-connection lines DB3 being arranged to extend in the first direction X.

The present embodiment explains that the first common signal line DB1 and the second common signal line DB2 can be connected to each other through the sub-connection line DB3 extending along the first direction X, that is, the first common signal line DB1, the second common signal line DB2, and the sub-connection line DB3 are interlaced to each other to form a grid structure, so that only one pin (not shown in the drawings) for providing a common voltage signal needs to be provided on the flexible circuit board 40, and the common voltage signal is provided to all the driving circuits 601 of the driving circuit layer 60 through the pin for providing the common voltage signal and the sub-connection line DB3 for connecting the first common signal line DB1 and the second common signal line DB2 to each other, which is beneficial to reducing the number of pins on the flexible circuit board 40, and thus the occupied area of the flexible circuit board 40 can be reduced.

Optionally, the line width of the common signal line DB is greater than the line width W5 of the sub-connection line DB 3. The present embodiment further explains that since the sub-connection lines DB3 extending in the first direction X are not within the range covered by the dam walls 50, the line width W5 of the sub-connection lines DB3 may be set narrow, for example, the line width W5 of the sub-connection lines DB3 may be smaller than not only the line width W3 of the first common signal line DB1 but also the line width W4 of the second common signal line DB2, or the line width W5 of the sub-connection lines DB3 may be equal to the line width W4 of the second common signal line DB2 but smaller than the line width W3 of the first common signal line DB1 (as shown in fig. 12), and the sub-connection lines DB3 may avoid occupying too much space of the driving circuit layer 60.

In some optional embodiments, please refer to fig. 12, fig. 13, and fig. 14 to fig. 16 in combination, fig. 14 is a schematic diagram of an equivalent circuit connection structure of a plurality of driving circuits of a driving circuit layer according to an embodiment of the present invention, fig. 15 is a schematic diagram of a connection structure of a driving circuit in fig. 14, fig. 16 is a timing diagram of an operation of the driving circuit, the driving circuit layer 60 according to the present embodiment includes a plurality of driving circuits 601, and further includes a Scan line Scan, a detection signal line Data, a power signal line Vcc, a sampling signal line SP, and a common signal line DB; the driving circuit 601 includes a first transistor M1, a second transistor M2, a third transistor M3, and a storage capacitor Cp; wherein the content of the first and second substances,

the first electrode 101 of the first electrode layer 10 is connected to the storage node Xn;

a gate of the first transistor M1 is connected to the storage node Xn, a first pole of the first transistor M1 is connected to the power signal line Vcc, and a second pole of the first transistor M1 is connected to a first pole of the third transistor M3;

the gate of the second transistor M2 is connected to the sampling signal line SP, the first pole of the second transistor M2 is connected to the storage node Xn, and the second pole of the second transistor M2 is connected to the common signal line DB;

the grid electrode of the third transistor M3 is connected with the Scan line Scan, and the second pole of the third transistor M3 is connected with the detection signal line Data;

a first pole of the storage capacitor Cp is connected to the storage node Xn, and a second pole of the storage capacitor Cp is connected to the power signal line Vcc.

The driving circuit layer 60 of this embodiment is provided with a plurality of driving circuits 601 arranged in an array, and optionally, each driving circuit 601 may be electrically connected to one first electrode 101 of the first electrode layer 10 through a storage node Xn, so as to implement a fingerprint identification function. The driving circuit layer 60 includes a plurality of Scan lines Scan, a plurality of detection signal lines Data, a plurality of power signal lines Vcc, a plurality of sampling signal lines SP, and a plurality of common signal lines DB, wherein the Scan lines Scan, the plurality of detection signal lines Data, the plurality of power signal lines Vcc, the plurality of sampling signal lines SP, and the plurality of common signal lines DB may be electrically connected to the flexible circuit board 40 to implement input and output of signals. The Scan line Scan is used for providing a Scan signal to the driving circuit 601 and controlling the third transistor M3 to be turned on and off; the detection signal line Data is used for receiving a signal reflecting the condition of storing electric charge in the storage capacitor Cp when the third transistor M3 is turned on, that is, after fingerprint detection; the power supply signal line Vcc is used to provide the working power supply of the driving circuit 601, and the sampling signal line SP is used to control the on and off of the second transistor M2; the common signal line DB is used to provide the common voltage signal to the driving circuit 601 when the second transistor M2 is turned on. As shown in fig. 16, the operation phase of the driving circuit 601 of the present embodiment includes an excitation phase T1, a sampling phase T2, and a reading phase T3:

when a touch event occurs, firstly, in an excitation stage T1, only the second electrode 301 related to the touch event is provided with an alternating current Signal (excitation Signal) through the flexible circuit board 40, and the other second electrodes 301 are not provided with signals, so that only the driving voltage loaded between the first electrode 101 and the second electrode 301 at the position where the touch event occurs is changed continuously, and the piezoelectric layer 20 generates vibration to emit ultrasonic waves;

following the sampling period T2, the aftershock of the ultrasonic oscillation after the excitation period T1 ends affects the piezoelectric layer 20 to generate an electrical signal, and since the fingerprint includes a valley and a ridge, the intensity of the ultrasonic vibration reflected by the fingerprint back to the piezoelectric layer 20 is different, so that the change of the electrical signal generated by the reflection of the valley and the ridge back to the piezoelectric layer 20 is different, and the electrical signal generated by the piezoelectric layer 20 with different changes is converted into a different stored charge in the storage capacitor Cp through sampling;

and finally, in a reading stage T3, judging the positions of valleys and ridges in the fingerprint according to the electric signals with different changes, feeding the judgment result back to the first electrode 101 at the position where the touch event occurs, detecting different conditions of charges stored in the storage capacitor Cp after receiving and reflecting the detection result by the signal line Data, reading by the flexible circuit board 40, converting the Data to form a fingerprint image, and finishing fingerprint identification work.

The present embodiment explains that the first electrode 101 of the first electrode layer 10 is connected to the storage node Xn, so that the fingerprint electric signal received by the first electrode 101 can be stored in the storage capacitor Cp; the signal reading unit formed by the first transistor M1 and the third transistor M3 is used for reading the fingerprint electric signal stored in the storage capacitor Cp, that is, the voltage signal received by the first electrode 101, the first electrode of the first transistor M1 is connected with the fixed voltage input by the power signal line Vcc, the gate of the third transistor M3 is connected with the Scan line Scan, and the Scan line Scan can input an instruction whether to read out the detection signal, so that the third transistor M3 is turned on, and the fingerprint electric signal stored in the storage capacitor Cp is output through the detection signal line Data. In the process of storing the fingerprint electrical signal received by the first electrode 101 in the storage capacitor Cp, the second transistor M2 may be turned on by the sampling signal line SP, and a common voltage signal is applied to the second pole of the second transistor M2 through the common signal line DB, so that the alternating voltage signal received by the first electrode 101 is increased, and a fingerprint detection signal with a relatively high contrast is obtained.

It can be understood that, the present embodiment provides a connection structure of a driving circuit 601 capable of completing fingerprint identification by using an ultrasonic technology, but is not limited to this circuit structure, and in a specific implementation, the connection structure may be other detection circuits capable of realizing ultrasonic fingerprint identification, a working timing diagram of the driving circuit 601 illustrated in fig. 16 is only an example provided in the present embodiment, the driving circuit 601 provided in the present embodiment may also adopt other timing sequences for driving according to an actual situation, and details of the present embodiment are not described herein.

In some alternative embodiments, please refer to fig. 12, fig. 13, fig. 14 to fig. 16 in combination, in this embodiment, the Scan lines Scan are disposed along the second direction Y.

In the driving circuit layer 60, the extending direction of the Scan line Scan connected to each driving circuit 601 is the same as the extending direction of the second electrode 301, and both the Scan lines Scan are arranged to extend along the second direction Y, when a touch event occurs, the flexible circuit board 40 provides an alternating current signal only for the second electrode 301 related to the touch event through the driving circuit 601, and the flexible circuit board 40 provides a driving signal only for the Scan line Scan corresponding to the second electrode 301 related to the touch event, so that only the multiple rows of driving circuits 601 corresponding to the second electrode 301 related to the touch event can be driven to complete the fingerprint identification operation, which is beneficial to reducing power consumption.

In some alternative embodiments, please refer to fig. 8 and fig. 11 in combination, in the present embodiment, an orthographic projection of the dam 50 to the plane of the first electrode layer 10 does not overlap with the first electrode 101.

In the plane parallel to the first electrode layer 10, the retaining walls 50 between two adjacent second electrodes 301 are located between two adjacent columns of the first electrodes 101, that is, the orthographic projection of the retaining walls 50 to the plane of the first electrode layer 10 is not overlapped with the first electrodes 101, so that the overlapping of the first electrodes 101 and the retaining walls 50 can be avoided as much as possible, the facing area of the second electrodes 301 and each corresponding first electrode 101 can be increased, the influence of the staggering of the first electrodes 101 and the second electrodes 301 on the driving voltage loaded between the first electrodes 101 and the second electrodes 301 can be avoided, and the accuracy of fingerprint identification can be improved.

In some alternative embodiments, please refer to fig. 8 and 11 in combination, in the present embodiment, the width W6 of the retaining wall 50 along the first direction X ranges from 1 um to 50um.

The embodiment explains that the retaining wall 50 disposed between two adjacent second electrodes 301 can be wider, the width W6 range of the retaining wall 50 is 1-50um, the too small width W6 of the retaining wall 50 is not beneficial to increasing the line width of the common signal line DB overlapped with the retaining wall 50 to achieve the purpose of reducing power consumption, and the too large width W6 of the retaining wall 50 affects the layout area of the second electrodes 301, so the setting of the width W6 range of the retaining wall 50 in the embodiment as 1-50um is not only beneficial to increasing the line width of the common signal line DB overlapped with the retaining wall 50, and further more effective reduction of power consumption, and it can be ensured that the second electrode layer 30 has enough space to layout of the second electrodes 301 as much as possible.

In some alternative embodiments, please refer to fig. 8 and 11 in combination, in this embodiment, the material of the retaining wall 50 includes an organic material.

The embodiment explains that the material for manufacturing the retaining wall 50 may be an organic material, such as acrylic, polyimide or other resin material, and the organic material has a good buffering performance, so that the retaining wall 50 can play an insulating role and also play a role in buffering the pressure between two adjacent second electrodes 301. In addition, in the manufacturing process, generally, the retaining wall 50 of the embodiment is made of an organic material, which is convenient for coating, so that a thicker film layer can be conveniently formed as the retaining wall 50 of the embodiment.

Optionally, when the second electrode 301 of this embodiment is manufactured, since the second electrode 301 has a high requirement on precision, and a pattern with high precision cannot be formed by a photolithography process and other processes, in this embodiment, when the second electrode 301 is manufactured, the pattern may be formed by using the retaining wall 50, that is, the piezoelectric layer 20 is first coated with an organic material layer, and the plurality of retaining walls 50 are formed by the photolithography process, and then the second electrode layer 30 is formed by using a coating process, and due to the action of the retaining walls 50, the second electrode 301 extending along the second direction Y with high precision may be formed between adjacent retaining walls 50, so that the second electrode 301 is directly bonded and connected to the flexible circuit board 40.

In some alternative embodiments, with continuing reference to fig. 8 and 11, in this embodiment, the difference between the acoustic resistance of the material forming the retaining wall 50 and the acoustic resistance of the first electrode 101 and the second electrode 301 is less than or equal to 9 mrayl. The acoustic resistance is a characteristic of a material, and refers to a complex ratio of sound pressure of a medium on a certain area of a wave front to a volume velocity passing through the area, that is, resistance that needs to be overcome by displacement of the medium when the acoustic wave is conducted, the larger the acoustic resistance is, the larger the sound pressure needed to push the medium is, the smaller the acoustic resistance is, the smaller the sound pressure is, and a measurement value of the acoustic impedance is usually in a unit of megarayleigh (MRayl).

This embodiment explains that the acoustic resistance of the material for manufacturing the retaining wall 50 can be set to be close to the acoustic resistances of the first electrode 101 and the second electrode 301, that is, the difference between the acoustic resistance of the material for manufacturing the retaining wall 50 and the acoustic resistances of the first electrode 101 and the second electrode 301 is less than or equal to 9 mrayleys, and the phenomenon of ultrasonic waveform distortion near the retaining wall 50 can be avoided when ultrasonic fingerprint identification is performed.

In some alternative embodiments, please refer to fig. 8 and fig. 11 in combination, in this embodiment, a surface of the retaining wall 50 close to the first electrode layer 10 is a first surface 50A, a surface of the second electrode 301 close to the first electrode layer 10 is a second surface 301A, and the first surface 50A and the second surface 301A are located on the same plane.

The embodiment explains that the first surface 50A of the retaining wall 50 close to the first electrode layer 10 and the second surface 301A of the second electrode 301 close to the first electrode layer 10 are on the same plane, so that the retaining wall 50 can be ensured not to extend to the piezoelectric layer 20 as much as possible, the retaining wall 50 can be prevented from damaging the uniformity of the piezoelectric layer 20, and the uniformity of the piezoelectric layer 20 when generating vibration and emitting ultrasonic waves can be improved.

In some optional embodiments, please refer to fig. 1-16 and fig. 17 in combination, in which fig. 17 is a schematic plan view of a display panel according to an embodiment of the present invention, and the display panel 111 according to the embodiment includes the fingerprint identification module 000 according to the above embodiment of the present invention. The embodiment in fig. 17 is only an example of a mobile phone, and the display panel 111 is described, it is to be understood that the display panel 111 provided in the embodiment of the present invention may be a display panel 111 with other display functions, such as a computer, a television, a vehicle-mounted display panel, and the present invention is not limited in this regard. The display panel 111 provided in the embodiment of the present invention has the beneficial effect of the fingerprint identification module 000 provided in the embodiment of the present invention, and specific descriptions of the fingerprint identification module 000 in the above embodiments may be specifically referred to, and this embodiment is not described herein again.

It can be understood that, in the embodiment, the area of the display panel 111 is not equal to the area of the fingerprint identification module 000 for example, the fingerprint identification module 000 may be disposed only in an area where fingerprint identification is required (as shown in fig. 17), but not limited thereto, the area of the display panel 111 may be close to the same as the area of the fingerprint identification module 000, so that full-screen fingerprint identification can be achieved.

In some alternative embodiments, please refer to fig. 1-16, 17 and 18 in combination, fig. 18 is a schematic cross-sectional structure view along direction F-F' in fig. 17, in which the fingerprint identification module 000 is located on a side away from the light emitting surface G of the display panel 000, and the first electrode layer 10 is located on a side of the second electrode layer 30 close to the display panel 111 of the present embodiment. Optionally, the display panel 111 may include a display module 222 disposed opposite to the fingerprint identification module 000, where the display module 222 may be a liquid crystal display module including an array substrate, a liquid crystal layer, a color film substrate, and the like, or the display module 222 may also be an organic light emitting display module including an organic light emitting layer, an encapsulation layer, and the like, and this embodiment is not limited in particular.

The embodiment explains that the display panel 111 includes the fingerprint identification module 000, the fingerprint identification module 000 may be disposed on a side away from the light emitting surface G of the display panel 000, and the first electrode layer 10 is disposed on a side of the second electrode layer 30 close to the display panel 111, optionally, an insulating protection layer 80 (not filled in the drawing) may be disposed on a side of the second electrode layer 30 away from the first electrode layer 20, so as to protect the fingerprint identification module 000.

The fingerprint identification module 000 of the present embodiment may be disposed on a side away from the light emitting surface G of the display panel 000, and the first electrode layer 10 is disposed on a side of the second electrode layer 30 close to the display panel 111, because the ultrasonic wave is reflected by the air interface, the fingerprint identification module 000 is disposed on a side away from the light emitting surface G of the display panel 000 in the present embodiment, and the first electrode layer 10 is disposed on a side of the second electrode layer 30 close to the display panel 111, that is, the fingerprint identification module 000 is inversely attached to the display panel 000, so that the ultrasonic signal of the reflection portion can be better utilized, which is favorable for improving the fingerprint identification precision.

It can be understood that the display panel 111 of the present embodiment may be a liquid crystal display panel, and may also be an organic light emitting display panel, fig. 17 and fig. 18 of the present embodiment are only exemplary structures of the display panel 111, and in specific implementation, the structures of the display panel 111 may be understood with reference to the structures of the display panels in the related art.

In some optional embodiments, please refer to fig. 1-16, 17 and 19 in combination, fig. 19 is a schematic cross-sectional view along direction F-F' in fig. 17, in which the display panel 111 further includes a touch layer 70, and the touch layer 70 is located on a side close to the light-emitting surface G of the display panel 111. Optionally, when the display module 222 is a liquid crystal display module including an array substrate, a liquid crystal layer, a color film substrate, and the like, the touch layer 70 may be fabricated on a side of the color film substrate of the display module 222 away from the liquid crystal layer, and optionally, when the display module 222 is an organic light emitting display module including an organic light emitting layer, an encapsulation layer, and the like, the touch layer 70 may be fabricated on a side of the encapsulation layer away from the organic light emitting layer, and then the touch layer 70 is disposed in the display panel 111 through a protection structure such as a cover plate 90 (not shown in the drawings).

This embodiment explains that the display panel 111 further includes the touch layer 70, the touch layer 70 is located on the side close to the light emitting surface G of the display panel 111, so that the display panel 111 can realize a touch function, the touch layer 70 determines the position where the touch event occurs, and the touch position detection work is completed, and then the fingerprint recognition module 000 performs fingerprint recognition only on the position where the touch event occurs, so that an additional touch device such as a capacitive touch panel is not needed, and thus the cost of the display panel can be reduced, and meanwhile, the fingerprint recognition module 000 in the above embodiments can also complete the fingerprint recognition work, and the power consumption can be reduced.

In some optional embodiments, please refer to fig. 1 to 16, 17, 19 and 20 in combination, where fig. 20 is a schematic flow chart of a driving method of a display panel according to an embodiment of the present invention, the driving method provided in this embodiment is used for driving the display panel according to the above embodiment to perform touch detection and fingerprint identification, and the driving method includes:

s10: determining the touch position of the finger through the touch layer 70 to complete the touch detection work;

s20: determining a second electrode 301 corresponding to the finger touch position;

s30: supplying an excitation signal to only the second electrode 301 corresponding to the finger touch position, connecting the first electrode 101 to a common potential, and generating an ultrasonic wave by the piezoelectric layer 20 between the second electrode 301 corresponding to the finger touch position and the first electrode 101;

s40: the driving circuit 601 corresponding to the second electrode 301 corresponding to the finger touch position performs ultrasonic fingerprint identification to complete fingerprint identification.

Specifically, according to the driving method of the display panel provided by this embodiment, when fingerprint identification is performed after touch detection is completed, each second electrode 301 is driven separately, that is, when a touch event occurs, the flexible circuit board 40 only provides an alternating current signal for the second electrode 301 related to the touch event, and the remaining second electrodes 301 do not provide a signal, only the driving voltage loaded between the first electrode 101 and the second electrode 301 at the position where the touch event occurs changes continuously, so that the piezoelectric layer 20 generates vibration and generates ultrasonic waves, because the fingerprint includes valleys and ridges, the vibration intensity of the ultrasonic waves reflected back to the piezoelectric layer 20 by the fingerprint differs, so that the changes of the electric signals generated by the valleys and the ridges reflected back to the piezoelectric layer 20 are different, the positions of the valleys and the ridges in the fingerprint are determined according to the voltage signals that vary, and the determination result is fed back to the first electrode 101 at the position where the touch event occurs, and finally the flexible circuit board 40 can read and perform data conversion to form a fingerprint image, so as to complete the fingerprint identification, when the touch event occurs, the flexible circuit board 40 only provides an alternating current signal for the second electrode 301 related to provide no signal, so that the area of the alternating current signal, and further reduce the power consumption of the driving load, which is beneficial to reduce the load.

Optionally, please refer to fig. 1 to 16, 17, 19 and 21 in combination, where fig. 21 is another schematic flow chart of a driving method of a display panel according to an embodiment of the present invention, the driving method provided in this embodiment is used for driving the display panel according to the foregoing embodiment to perform touch detection and fingerprint identification, and the driving method includes:

s20: determining a second electrode 301 corresponding to the touch position of the finger;

s301: in the excitation stage, only the second electrode 301 corresponding to the finger touch position is provided with an alternating current signal, and the piezoelectric layer 20 generates vibration and emits ultrasonic waves;

s302: in the sampling stage, the ultrasonic wave returns to the piezoelectric layer 20 from the fingerprint valley and fingerprint ridge of the finger, the piezoelectric layer 20 generates different electric signals, and the different electric signals are converted into different stored charges of the storage capacitor Cp in the driving circuit 601 through sampling;

s303: in the reading stage, a scanning signal is fed into a scanning line Scan, and the stored charges of the storage capacitor Cp of each driving circuit 601 are read through a detection signal line Data;

s40: the flexible circuit board 40 reads and converts data to form a fingerprint image, and the fingerprint identification work is completed.

In this embodiment, the process of performing fingerprint recognition after touch detection is completed is explained, and after the position where a touch event occurs is determined, in the excitation stage T1, only the second electrode 301 involved in the touch event is provided with an alternating current Signal (excitation Signal) through the flexible circuit board 40, and the remaining second electrodes 301 are not provided with signals, so that only the driving voltage loaded between the first electrode 101 and the second electrode 301 where the touch event occurs is changed continuously, so that the piezoelectric layer 20 generates vibration and emits ultrasonic waves; following the sampling period T2, the aftershock of the ultrasonic oscillation after the excitation period T1 ends affects the piezoelectric layer 20 to generate an electrical signal, and since the fingerprint includes a valley and a ridge, the intensity of the ultrasonic vibration reflected by the fingerprint back to the piezoelectric layer 20 is different, so that the change of the electrical signal generated by the reflection of the valley and the ridge back to the piezoelectric layer 20 is different, and the electrical signal generated by the piezoelectric layer 20 with different changes is converted into a different stored charge in the storage capacitor Cp through sampling; and finally, in a reading stage T3, the positions of valleys and ridges in the fingerprint are judged according to the electric signals with different changes, the judgment result is fed back to the first electrode 101 at the position where the touch event occurs, the detection signal line Data receives different conditions reflecting the stored charges in the storage capacitor Cp, and the detection signal line Data is read by the flexible circuit board 40 and carries out Data conversion to form a fingerprint image, so that the fingerprint identification work is completed.

In some alternative embodiments, please refer to fig. 22, where fig. 22 is a schematic plane structure diagram of a display device according to an embodiment of the present invention, and the display device 1111 provided in this embodiment includes the display panel 111 according to the above embodiment of the present invention. The embodiment of fig. 22 only uses a mobile phone as an example to describe the display device 1111, but it should be understood that the display device 1111 provided in the embodiment of the present invention may be other display devices 1111 having a display function, such as a computer, a television, a vehicle-mounted display panel, and the present invention is not limited thereto. The display device 1111 provided in the embodiment of the present invention has the beneficial effects of the display panel 111 provided in the embodiment of the present invention, and specific reference may be made to the specific description of the display panel 111 in the foregoing embodiments, which is not repeated herein.

According to the embodiment, the fingerprint identification module, the display panel and the display device provided by the invention at least realize the following beneficial effects:

the fingerprint identification module in the invention is provided with a second electrode layer comprising a plurality of second electrodes, the second electrodes can be used as driving electrodes, and the flexible circuit board used for providing driving voltage signals for the fingerprint identification module and reading fingerprint detection signals is directly bound and connected with the second electrodes. In the prior art, the second electrode is generally connected with the flexible circuit board through a thin lead wire to realize the transmission of electric signals, the difference between the width of the lead wire used as a routing wire and the width of the second electrode used as a driving electrode is larger, and the width of the common routing wire is much smaller, even only a few hundredths or even a few thousandths of the width of the second electrode; the size of the line width affects the size of the cross-sectional area of the resistor, and thus the size of the resistor, and the smaller the line width, the smaller the cross-sectional area, the larger the resistance, so that the resistance of the lead used as a trace is much larger than the resistance of the second electrode used as a driving electrode under otherwise substantially the same conditions. Therefore, the flexible circuit board used for providing a driving voltage signal for the fingerprint identification module and reading a fingerprint detection signal is directly bound and connected with the second electrode, and a lead is not used in the module structure, so that the serious power loss caused by the loss of the driving signal transmitted between the flexible circuit board and the second electrode due to the fact that the impedance of the lead is large can be effectively avoided, the power loss of the fingerprint identification module can be further reduced, ultrasonic fingerprint identification is achieved, the identification performance is improved, meanwhile, when a touch event occurs, the flexible circuit board only provides an alternating current signal for the second electrode related to the touch event, the rest of the second electrodes do not provide signals, the power supply area can be further reduced, the capacitance load during driving is reduced, and the purpose of reducing power consumption is further achieved.

Although some specific embodiments of the present invention have been described in detail by way of examples, it should be understood by those skilled in the art that the above examples are for illustrative purposes only and are not intended to limit the scope of the present invention. It will be appreciated by those skilled in the art that modifications may be made to the above embodiments without departing from the scope and spirit of the invention. The scope of the invention is defined by the appended claims.

Claims

1. The utility model provides a fingerprint identification module which characterized in that includes:

the first electrode layer comprises a plurality of first electrodes which are arranged in an array;

a piezoelectric layer on one side of the first electrode layer;

a second electrode layer located on a side of the piezoelectric layer away from the first electrode layer, the second electrode layer including a plurality of second electrodes arranged in a first direction, one of the second electrodes overlapping at least two of the first electrodes; the length of the second electrode along the first direction is A, and the length of the second electrode along the second direction is B, wherein B is more than A;

the flexible circuit board is partially overlapped with the second electrode along the direction perpendicular to the plane of the second electrode layer, and the flexible circuit board is bound and connected with the second electrode;

the second electrode and the flexible circuit board are arranged along the second direction in a plane parallel to the first electrode layer;

wherein the first direction intersects the second direction.

2. The fingerprint identification module of claim 1, wherein the flexible circuit board comprises a plurality of pins, and one of the second electrodes is bonded to one of the pins.

3. The fingerprint recognition module of claim 1, wherein the second electrode is rectangular in shape.

4. The fingerprint recognition module of claim 3, wherein A is 2mm ≦ A ≦ 5mm and B > 5mm.

5. The fingerprint identification module of claim 1,

and a retaining wall is arranged between every two adjacent second electrodes.

6. The fingerprint identification module of claim 5, wherein the retaining wall extends along the second direction, and an orthographic projection of the retaining wall to a plane where the flexible circuit board is located is at least partially overlapped with the flexible circuit board.

7. The fingerprint identification module of claim 5, further comprising a driving circuit layer electrically connected to the first electrode layer;

the driving circuit layer comprises a plurality of driving circuits which are arranged in an array;

in a plane parallel to the first electrode layer, the interval between two adjacent second electrodes is located between two adjacent columns of the driving circuits.

8. The fingerprint identification module of claim 7, wherein the driving circuit layer includes at least a common signal line, and the common signal line extends along the second direction; the common signal line includes at least a first common signal line;

the first common signal line at least partially overlaps with the front projection of the retaining wall to the plane of the first electrode layer.

9. The fingerprint identification module of claim 8, wherein the common signal line further comprises a second common signal line, an orthographic projection of the second common signal line to the plane of the first electrode layer is not overlapped with an orthographic projection of the retaining wall to the plane of the first electrode layer, and a line width of the second common signal line is smaller than a line width of the first common signal line.

10. The fingerprint identification module of claim 8,

the driving circuit layer further comprises a plurality of sub-connecting lines, the sub-connecting lines are connected with each other through the common signal line, and the sub-connecting lines extend along the first direction.

11. The fingerprint identification module of claim 10,

the line width of the common signal line is greater than the line width of the sub-connecting lines.

12. The fingerprint identification module of claim 8, wherein the driving circuit comprises a first transistor, a second transistor, a third transistor, a storage capacitor; the driving circuit layer also comprises a scanning line, a detection signal line, a power signal line and a sampling signal line;

the first electrode is connected with a storage node;

a gate of the first transistor is connected to the storage node, a first pole of the first transistor is connected to the power signal line, and a second pole of the first transistor is connected to a first pole of the third transistor;

a gate of the second transistor is connected to the sampling signal line, a first pole of the second transistor is connected to the storage node, and a second pole of the second transistor is connected to the common signal line;

a gate of the third transistor is connected to the scan line, and a second pole of the third transistor is connected to the detection signal line;

a first pole of the storage capacitor is connected to the storage node, and a second pole of the storage capacitor is connected to the power signal line.

13. The fingerprint recognition module of claim 12, wherein the scan line extends along the second direction.

14. The fingerprint identification module of claim 5, wherein an orthographic projection of the retaining wall onto a plane where the first electrode layer is located does not overlap with the first electrode.

15. The fingerprint identification module of claim 5, wherein the width of the retaining wall along the first direction is in a range of 1-50um.

16. The fingerprint identification module of claim 5, wherein the retaining wall is made of a material comprising an organic material.

17. The fingerprint identification module of claim 5, wherein a difference between an acoustic resistance of a material forming the retaining wall and acoustic resistances of the first electrode and the second electrode is less than or equal to 9 Mrayls.

18. The fingerprint identification module of claim 5, wherein a surface of the retaining wall adjacent to the first electrode layer is a first surface, a surface of the second electrode adjacent to the first electrode layer is a second surface, and the first surface and the second surface are located on a same plane.

19. A display panel comprising the fingerprint recognition module of any one of claims 1-18.

20. The display panel of claim 19, wherein the fingerprint identification module is located on a side away from the light emitting surface of the display panel, and the first electrode layer is located on a side of the second electrode layer close to the display panel.

21. The display panel according to claim 19, further comprising a touch layer on a side close to a light-emitting surface of the display panel.

22. A driving method of a display panel for driving the display panel of claim 21 for a touch detection operation and a fingerprint recognition operation, the driving method comprising:

determining the touch position of the finger through the touch layer to finish touch detection work;

determining the second electrode corresponding to the finger touch position;

providing an excitation signal only to the second electrode corresponding to the finger touch position, the first electrode being connected to a common potential, the piezoelectric layer between the second electrode and the first electrode corresponding to the finger touch position generating an ultrasonic wave;

and the driving circuit corresponding to the second electrode corresponding to the finger touch position carries out ultrasonic fingerprint identification to complete fingerprint identification work.

23. The method for driving a display panel according to claim 22, wherein the fingerprint recognition operation includes:

in the excitation stage, only the second electrode corresponding to the finger touch position is provided with an alternating current signal, and the piezoelectric layer generates vibration and emits ultrasonic waves;

in the sampling stage, the ultrasonic waves return to the piezoelectric layer from fingerprint valleys and fingerprint ridges of the fingers, the piezoelectric layer generates different electric signals, and the different electric signals are converted into different storage charges of a storage capacitor in the driving circuit through sampling;

and in the reading stage, scanning signals are fed into scanning lines, and the storage charges of the storage capacitors of the driving circuits are read through detecting signal lines, so that the fingerprint identification work is completed.

24. A display device characterized by comprising the display panel according to any one of claims 19 to 21.